For PayPal integration all their documentation tells you to call server-side script running on Node.js, and here the client-side call to the CreateOrder function in the server:

        async createOrder() {
                const response = await fetch("/api/orders", {
                    method: "POST",
                    headers: {
                        "Content-Type": "application/json",
                    },
                    body: JSON.stringify({
                        cart: [
                            {
                                id: "NQ888P",
                                quantity: "3",
                            },
                        ],
                    }),
                });

But there is not a single document on this much better alternative: The code below, 100% running from client, does not call any server-side script at all. It goes straight to PayPal’s site and does the same or even better job than the mechanism above:

    createOrder: function (data, actions) {
        return actions.order.create({
            intent: 'CAPTURE',
            purchase_units: [{
                amount: {
                    value: "14.99",
                    currency_code: "USD"
                }
            }]
        })
    },

This code can only be found in stackoverflow and other forums. So does anyone know why PayPal suppresses the client-only mechanism from all the documents?